【单选题】分类是化学研究中常用的方法,下列分类方法中,正确的是( )
A.
NO 2 、SiO 2 、CO均为酸性氧化物
【单选题】What important discovery about seismic waves does the instructor mention?
A.
They occur at regular intervals.
B.
They can withstand great heat.
C.
They travel through the Earth's interior.
D.
They can record the Earth's internal temperature.
【简答题】A) speak B) talk C) tell D) mention
【简答题】IP 地址195.110.20.67 默认包含的可用主机地址数为____。
【单选题】下列物质分类正确的是( )
A.
SO 2 、SiO 2 、CO均为酸性氧化物
【简答题】r__________ mention of a person, an occurrence or a situation
【简答题】r____ to mention or speak aboutsb.or sth. 提到;谈到